Patent GB-490668-A (GB)
Title: Improvements in or relating to coverings or finishes of sheet material for walls, ceilings, floors and other surfaces
IPC: B32B13/14
Filed: 1936-12-18
Abstract: 490,668. Wall and ceiling coverings ; flooring. LEFEBURE, V., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. Dec. 18, 1936, No. 34910. [Classes 20 (iv) and 107] A method of finishing walls, ceilings, floors, and other surfaces comprises mounting on or securing in any suitable manner to the surface to be finished, a composite board material which has been made by allowing a layer of a water-setting plaster or cement to set while in contact on both sides with relatively thin liners of fibrous material, e.g. pulpboard, and subsequently removing the exposed liner from the underlying mineral core by stripping and/or abrasion, With the aid of water. The composite board material used is preferably that made by the process described and claimed in Specification 490,667. The liner next to the surface to be finished is preferably waterproofed, e.g. by applying an aqueous emulsion of bitumen thereto prior to affixing the board to the surface to be finished or by using a board one liner of which has been rendered waterproof during its manufacture. The mineral core of the board, which preferably consists of a calcium sulphate plaster and in particular plaster of Paris or anhydrite plaster, may be made from mixes containing gas or foam producing agents so as to give it a void or cellular structure. The core may also be of a decorative nature, e.g. it may consist of coloured, mottled or veined plaster, or of a plaster containing coloured aggregates, which can be abraded to give a terrazzo surface. If desired, reinforcements, such as wire gauze or perforated pulpboard, may be included in the mineral core. The top surface of this core which is exposed by the removal of the liner may be left as such or it may be rubbed with an abrasive to bring out veined or terrazzo effects. The final surface may be painted, lacquered or impregnated with oil or wax or other filling materials. If the surface to be finished consists of masonry or the like, the board is preferably affixed thereto by means of plaster or cement forming either a continuous or a broken layer between the board and the surface to be finished. Moulded concrete walls, ceilings, floors and the like may be finished by arranging that the board forms part of the mould or a lining for the mould, allowing the concrete to set while in contact with the board and subsequently removing the exposed liner. A number of examples are described in one of which one or both of the liners consist of two or more fibrous layers united by a water-soluble or water-softening adhesive. The layer to be placed next to the plaster is thin compared with the total thickness of the liner, e.g. it may be made of thin paper. With this arrangement, when the surface of the final product is moistened after the material has been affixed to the surface to be finished, the water penetrates to the adhesive bond between the relatively thin fibrous layer and the superposed layer or layers, and the latter may be stripped off leaving the plaster core with a thin fibrous covering which can easily be removed by washing and rubbing. In a further example, one or both of the liners consist of two or more plies, it being arranged that a plane of weakness exists between the two plies. The outer ply is preferably the thicker one so that the plane of weakness will be close to the core. After the board has been mounted on the surface to be finished, the outer ply is stripped off and the residual thin ply is removed by wetting and abrasion.